As a leading international authority on toxic chemicals, Professor John P. Giesy is in the top percentile of active authors in the world. His resume is littered with accolades, from being named in the Who’s Who of the World to receiving the Einstein Professor Award from the Chinese Academy of Sciences. Professor Giesy was credited with being the first scientist to discover toxic per- and poly-fluoroalkyl [PFAS] chemicals in the environment, and with helping to persuade chemical giant 3M Company to abandon their manufacture. But Fairfax Media can now reveal that Professor Giesy was accused of covertly doing 3M’s bidding in a widespread international campaign to suppress academic research on the dangers of PFAS. A trove of internal company documents has been made public for the first time following a $US850 million ($1150 million) legal settlement between the company and Minnesota Attorney-General Lori Swanson. They suggest that Professor Giesy was one weapon in an arsenal of tactics used by the company to - in a phrase coined by 3M - “command the science” on the chemicals. The documents have allowed the state to chronicle how 3M, over decades, allegedly misled the scientific community about the presence of its chemicals in the public’s blood, undermined studies linking the chemicals with cancer and scrambled to selectively fund research to be used as a “defensive barrier to litigation”. Experts have branded the strategies nearly identical to those used historically by the tobacco and pharmaceutical industries. At least 90 communities across Australia are being investigated for elevated levels of the contaminants, including 10 in Sydney. The Australian government is aggressively defending a growing number of class actions from towns where the chemicals were used for decades in fire retardants on military bases, the runoff tainting the soil and water of surrounding homes. The Department of Health maintains there is “no consistent evidence” that the chemicals can cause “important” health effects such as cancer. In arguing this, its experts have made reference to the work of 3M scientists, who insist the chemicals are not harmful at the levels found in the blood of humans. On Saturday, Fairfax Media exposed cancer cluster fears centring on a high school in Oakdale, Minnesota, in America’s upper mid-west, a few blocks from 3M’s global headquarters and where the water was contaminated with PFAS. 3M has vigorously denied the allegations. It did not accept liability in February, when it reached a settlement on the courthouse steps over alleged damage to Minnesota’s natural resources and drinking water. A spokesperson said: “The vast body of scientific evidence, which consists of decades of research conducted by independent third parties and 3M, does not show that these chemistries negatively impact human health at current exposure levels”. But several leading public health agencies in the United States have sounded warnings to the contrary. In 2016, the United States Environmental Protection Agency found the “weight of evidence” supported the conclusion that the chemicals were a human health hazard, warning that exposure over certain levels could result in immune and developmental effects and cancer. The US National Toxicology Program found they were “presumed to be an immune hazard” based on high levels of evidence from animal studies and a moderate level from humans. Immune suppression - usually as a result of conditions such as organ transplant or HIV - is known to increase the risk of several types of cancer by making the immune system less able to detect and destroy cancer cells or fight cancer-causing infections. DuPont, which used PFAS chemicals in the manufacture of Teflon, reached a $US670 million settlement with residents living near its manufacturing plant in Ohio, West Virginia, last year, after an expert health panel conducted a large-scale epidemiological investigation. It concluded that residents’ drinking water, tainted with one of the chemicals called PFOA, had a “probable link” to six health conditions, including kidney and testicular cancer. One of 3M’s own material data safety sheets for a PFAS chemical included a warning that it could cause cancer in 1997 - that was subsequently removed - according to the Minnesota case. The chemical of greatest concern in Australia is perfluorooctane sulfonate, or PFOS, arguably the most toxic of the chemicals studied. This was widely used in Scotchgard and fire-fighting foams. Last month, there was a storm of controversy amid claims that the US EPA and the White House blocked the publication of a health study on PFAS carried out by the country’s Agency for Toxic Substances and Disease Registry. In emails leaked to Politico, a Trump administration aide warned that the report would be a “public relations nightmare” because it would show that the chemicals endangered human health at far lower levels than what the EPA had previously deemed safe. Health warnings were echoed by Harvard Professor Philippe Grandjean and Professor Jamie DeWitt of North Carolina State University in their expert testimonies for the State of Minnesota. Professor Grandjean argued that PFAS chemicals pose a “substantial present and potential hazard” to human health, including to immune, thyroid, liver, endocrine, cardiovascular and reproductive functions, and by “causing or increasing the risk of cancer”. “Both PFOA and PFOS show convincing associations with these outcomes,” he said, adding that risks to human health had been identified at very low exposure levels. To the outside world, Professor Giesy was a renowned and independent university academic. “But privately, he characterised himself as part of the 3M team,” alleged the State of Minnesota. “Despite spending most of his career as a professor at public universities, Professor Giesy has a net worth of approximately $20 million. This massive wealth results at least in part from his long-term involvement with 3M for the purpose of suppressing independent scientific research on PFAS.” Professor Giesy’s consulting company appears to have received payments from 3M between at least 1998 and 2009. One document indicated his going rate was about $US275 an hour. In an email to a 3M laboratory manager, Professor Giesy described his role as trying to keep “bad papers out of the literature”, because in “litigation situations they can be a large obstacle to refute”. Professor Giesy was an editor of several academic journals and, in any given year, about half of the papers submitted on PFAS came to him for review. “Some journals … for conflict-of-interest issues will not allow an industry to review a paper about one of their products. That is where I came in,” he wrote in another email. “In time sheets, I always listed these reviews as literature searches so that there was no paper trail to 3M.” Professor Giesy is alleged to have passed confidential manuscripts on to 3M, as well as an email from an EPA scientist detailing its latest PFAS investigations in Athens, Georgia. He allegedly bragged about rejecting the publication of at least one paper containing negative information about PFAS. In another email chain, a 3M manager was concerned that a study Professor Giesy had drafted was “suggestive” of possible PFAS health hazards and should be cushioned with an accompanying document on the health effects. “This paper … could set off a chain reaction of speculation that could reopen the issue with the media and move it back to a health story; something up to now we have avoided,” he wrote. Professor Giesy is based at the University of Saskatchewan in Canada, but he also holds positions with the University of Michigan and several Chinese universities. An internal 3M document referred to him needing to “buy favours” when developing joint projects with Chinese colleagues “over whom he can exert some influence”. A spokesperson for the University of Saskatchewan said it had conducted two reviews of Dr Giesy’s conduct. “We found nothing out of the ordinary or evidence of conflict of interest,” she said. The university stressed that the “vast majority” of Professor Giesy’s work for 3M was conducted while at Michigan State University, despite evidence of 3M payments to Professor Giesy’s consulting company after he arrived in Canada. Professor Giesy’s explanations included that these were “possibly” payments for previous work or studies by other employees of his consultancy. “He cannot be absolutely sure of the timing,” the university spokesperson said. “With respect to the emails … Dr Giesy explained to us that ‘bad papers’ referred to ‘bad science’ or ‘inaccurate’ papers or ‘poorly conducted’ research … and ‘no paper trail to 3M’ was due to the sensitivity of research findings conducted on PFAS produced by companies, primarily in foreign countries, other than 3M.” But several academics were furious with the university’s position. Professor Arthur Schafer, an expert in applied ethics at the University of Manitoba, slammed the explanation for the “no paper trail” comment as “ludicrously implausible”. “I don’t think it matters a hoot whether Giesy’s ethically questionable activities all took place prior to his coming on staff at the University of Saskatchewan or whether they continued,” he said. “The evidence points to deeply troubling conduct which, if confirmed by a proper investigation, should lead to disciplinary action - probably termination, given the seriousness of the behaviour.” One of the university’s council members, Professor Len Findlay, was unconvinced by the university’s reviews. “A key question remains: If the University of Saskatchewan had known much sooner about those emails between Giesy and 3M, would they still have recruited him? If so, what does that say about their desperation to buy a more illustrious institutional reputation and ranking through hires?” Professor Findlay said. “And what about 3M’s agreement to settle out of court, after delaying that action until the very last minute? What does that suggest about the nature of work undertaken on their behalf?” The actions of Professor Giesy were a jigsaw piece in a much broader puzzle, according to the State of Minnesota. It alleged that 3M: When 3M announced the voluntary phase-out of PFOS in 2000, it was presented as an environmentally responsible decision - costing the company $US480 million in annual revenue - and based on concerns over the discovery of PFOS in the blood of the general population in 1997. But according to internal documents, the company had actually made that discovery decades earlier, in the 1970s. Just before the phase-out announcement, the US EPA reviewed a PFOS study in rats, in which all of the offspring of the first generation died and many offspring of the second generation. “It is very unusual to see such second-generation effects,” the director of its Chemical Control Division wrote. About that time, scientist Richard Purdy quit 3M and copied the agency in on his resignation letter. He expressed “outrage” that his colleagues wanted to avoid collecting data on PFOS, which he described as “the most insidious pollutant” since polychlorinated biphenyl (PCB) and “probably worse”. PCB was an industrial chemical that was banned when it was found to be a human carcinogen. “I have worked to the best of my ability within the system to see that the right actions are taken on behalf of the environment,” he wrote. “Yet I see slow or no results. I am told the company is concerned, but their actions speak to different concerns than mine.” The failure of 3M to report information to the EPA on the adverse effects of the chemicals ultimately resulted in a $US1.5 million fine. In his testimony, Professor Grandjean argued that 3M had documented adverse effects in animals as early as the 1970s, with one researcher warning that PFOS was “certainly more toxic than anticipated”. 3M did not pursue findings of PFAS in the breast milk of animals, and published some of its studies after lags of 25 years, Professor Grandjean found. More concerning were several 3M-sponsored studies of its own exposed factory workers that showed elevated rates of prostate cancer, including statistically significant findings. One paper put the spike in prostate cancer deaths down to chance or because of the higher prevalence of prostate cancer in Minnesota. “Subsequent analyses provided to 3M … indicate that prostate cancer was actually less prevalent in Minnesota than in the US,” Professor Grandjean wrote. “Early studies of worker health inappropriately sought to explain away any possible associations with ill health.” In 1979, renowned scientist Dr Harold Hodge warned the company that if the chemicals were found to be widespread in the blood of the general population and had long half-lives, “we could have a serious problem”. The phrase was removed in a later document referring to the conversation. In another internal email, a 3M scientist wrote that one consideration as to whether a study should be done on reproductive effects was “the possibility of finding reproductive effects when conducting such a study”. Another controversy arose surrounding the work of a University of Minnesota thesis student, Frank Gilliland, who did early studies on 3M’s exposed factory workers. He found signs of hormonal and immune system abnormalities in males. But follow-up studies authored by 3M “undermined” these findings, Professor Grandjean said. Professor Grandjean has pioneered research into the effects of the chemicals on childhood vaccines, finding that as PFAS exposure doubled, vaccines were about half as effective in children in the Faroe Islands. A “substantial” number of children had such low levels of antibodies that they had virtually no protection against the diseases. He expressed concern about the scarcity of research into the effect of chemicals on infants and unborn children, who were exposed through cord blood and breast milk and were “likely more vulnerable to toxic effects”. It is no secret that 3M has poured significant funds into sponsoring PFAS research by consultancies and academic institutions. But the court documents indicate the company may have gone further - influencing studies but keeping its fingerprint hidden. According to court documents, the use of a “ghost writer” was floated at a 3M meeting in 2008. Professor Lisa Bero, of the University of Sydney, is internationally renowned for her investigations into the influence of industry on scientific research, as one of the first authors to scrutinise the tactics used by the tobacco and pharmaceutical companies. Much of her work has been based on documents that have come to light through litigation. “It’s directly parallel, I would have to say - the strategies that were used in the PFAS case are really all the same as we’ve seen used across the other industries,” she said. “Even the wording was identical.” One of the most interesting elements, she said, was that they all referred to scientific publication strategies. “That is all about generating evidence to either protect them from litigation or to market their products. It’s not about creating new scientific knowledge.” The key witness for 3M in the Minnesota case was Ellen Chang, a principal scientist at scientific consultancy Exponent. In her testimony, she argued that the weight of epidemiological evidence did not prove a causal link between exposure to PFAS and “specific adverse health outcomes in humans”. Exponent, based in California, has courted controversy on several occasions in the US, with some critics labelling it a “hired gun” producing science to meet the needs of corporations in messy courtroom battles. The firm has come under fire for casting doubt on studies linking second-hand smoke with cancer, as well as rates of lung cancer among mechanics exposed to brakes containing asbestos. “That criticism is quite simply factually wrong,” an Exponent spokesperson said. “We provide our clients with our engineering and scientific findings, which are frequently not what they would like to hear but rather what they need to know.” A 2016 study authored by Ms Chang reviewed all available evidence and concluded that PFAS exposure did not increase the risk of cancer in humans. The study was cited by toxicologists working for Australia’s Department of Defence as part of a human health risk assessment on exposed populations in Australia. It was also included in a report by the Department of Health’s expert panel on PFAS, which concluded that the current evidence did not support a “large impact” from PFAS exposure on a person’s health. However, the panel did admit that “important health effects” cannot be ruled out, and there was “fairly consistent” evidence linking PFAS exposure with changes in immune response, altered sex hormones, increased cholesterol, reduced kidney function and low birth weight. Professor Nicholas Buckley, of the University of Sydney, who chaired the panel, defended the use of Ms Chang’s studies in its review and argued that the “most importance guidance” came from other independent studies. “The major potential conflicts of interest for Chang’s 3M-funded reviews were noted in the PFAS report on multiple occasions, and the likely impact of that was considered,” he said. “Their results get summarised on about half-a-dozen pages in a 400-page report.” But lawyer Robert Bilott, who led the successful class action against Dupont in West Virginia, criticised the decision. “Papers prepared years after the fact to serve to manufacture doubt or perpetuate a false perception of uncertainty … with respect to PFOA should not be relied upon or cited as a basis for minimising or ignoring potential health risks,” he wrote. Dr Fardin Oliaei did not pause when asked whether 3M’s studies on the chemicals could be trusted, responding “of course not”. As a scientist with the Minnesota Pollution Control Agency, she was one of the first to begin investigating the spread of PFAS chemicals in the state. She alleges she was blocked from conducting her research and eventually forced out of her job, at a time when the agency was headed by Commissioner Sheryl Corrigan, a former high-ranking 3M manager. “The reality is this is a game, a dirty game of survival, of big industry,” said Dr Oliaei, who settled a whistleblower lawsuit filed in the federal court. “Seeing other scientists who lose their dignity and sleep in the same bed with this dirty corrupted industry? It’s heartbreaking. “But when I look at it in a global level ... here’s what it is: You just have to be someone that you can go to bed and put your head in peace on the pillow.” Cancer is killing these kids, and Australia should take note

As a leading international authority on toxic chemicals, Professor John P. Giesy is in the top percentile of active authors in the world.

His resume is littered with accolades, from being named in the Who’s Who of the World to receiving the Einstein Professor Award from the Chinese Academy of Sciences.

Professor Giesy was credited with being the first scientist to discover toxic per- and poly-fluoroalkyl [PFAS] chemicals in the environment, and with helping to persuade chemical giant 3M Company to abandon their manufacture.

But Fairfax Media can now reveal that Professor Giesy was accused of covertly doing 3M’s bidding in a widespread international campaign to suppress academic research on the dangers of PFAS.

Professor John Giesy was allegedly covertly doing 3M’s bidding in a widespread campaign to suppress academic research on the dangers of PFAS. Photo: Supplied

A trove of internal company documents has been made public for the first time following a $US850 million ($1150 million) legal settlement between the company and Minnesota Attorney-General Lori Swanson. They suggest that Professor Giesy was one weapon in an arsenal of tactics used by the company to - in a phrase coined by 3M - “command the science” on the chemicals.

The documents have allowed the state to chronicle how 3M, over decades, allegedly misled the scientific community about the presence of its chemicals in the public’s blood, undermined studies linking the chemicals with cancer and scrambled to selectively fund research to be used as a “defensive barrier to litigation”.

Experts have branded the strategies nearly identical to those used historically by the tobacco and pharmaceutical industries.

At least 90 communities across Australia are being investigated for elevated levels of the contaminants, including 10 in Sydney.

The Australian government is aggressively defending a growing number of class actions from towns where the chemicals were used for decades in fire retardants on military bases, the runoff tainting the soil and water of surrounding homes.

The Department of Health maintains there is “no consistent evidence” that the chemicals can cause “important” health effects such as cancer. In arguing this, its experts have made reference to the work of 3M scientists, who insist the chemicals are not harmful at the levels found in the blood of humans.

3M has vigorously denied the allegations. It did not accept liability in February, when it reached a settlement on the courthouse steps over alleged damage to Minnesota’s natural resources and drinking water.

A spokesperson said: “The vast body of scientific evidence, which consists of decades of research conducted by independent third parties and 3M, does not show that these chemistries negatively impact human health at current exposure levels”.

But several leading public health agencies in the United States have sounded warnings to the contrary.

In 2016, the United States Environmental Protection Agency found the “weight of evidence” supported the conclusion that the chemicals were a human health hazard, warning that exposure over certain levels could result in immune and developmental effects and cancer.

The US National Toxicology Program found they were “presumed to be an immune hazard” based on high levels of evidence from animal studies and a moderate level from humans.

Immune suppression - usually as a result of conditions such as organ transplant or HIV - is known to increase the risk of several types of cancer by making the immune system less able to detect and destroy cancer cells or fight cancer-causing infections.

DuPont, which used PFAS chemicals in the manufacture of Teflon, reached a $US670 million settlement with residents living near its manufacturing plant in Ohio, West Virginia, last year, after an expert health panel conducted a large-scale epidemiological investigation. It concluded that residents’ drinking water, tainted with one of the chemicals called PFOA, had a “probable link” to six health conditions, including kidney and testicular cancer.

One of 3M’s own material data safety sheets for a PFAS chemical included a warning that it could cause cancer in 1997 - that was subsequently removed - according to the Minnesota case.

The chemical of greatest concern in Australia is perfluorooctane sulfonate, or PFOS, arguably the most toxic of the chemicals studied. This was widely used in Scotchgard and fire-fighting foams.

A 3M advertisement for fire-fighting foam. Photo: Photo supplied

Last month, there was a storm of controversy amid claims that the US EPA and the White House blocked the publication of a health study on PFAS carried out by the country’s Agency for Toxic Substances and Disease Registry.

In emails leaked to Politico, a Trump administration aide warned that the report would be a “public relations nightmare” because it would show that the chemicals endangered human health at far lower levels than what the EPA had previously deemed safe.

Health warnings were echoed by Harvard Professor Philippe Grandjean and Professor Jamie DeWitt of North Carolina State University in their expert testimonies for the State of Minnesota.

Professor Grandjean argued that PFAS chemicals pose a “substantial present and potential hazard” to human health, including to immune, thyroid, liver, endocrine, cardiovascular and reproductive functions, and by “causing or increasing the risk of cancer”.

“Both PFOA and PFOS show convincing associations with these outcomes,” he said, adding that risks to human health had been identified at very low exposure levels.

Watching 'bad papers'

To the outside world, Professor Giesy was a renowned and independent university academic.

“But privately, he characterised himself as part of the 3M team,” alleged the State of Minnesota.

“Despite spending most of his career as a professor at public universities, Professor Giesy has a net worth of approximately $20 million. This massive wealth results at least in part from his long-term involvement with 3M for the purpose of suppressing independent scientific research on PFAS.”

Professor Giesy’s consulting company appears to have received payments from 3M between at least 1998 and 2009. One document indicated his going rate was about $US275 an hour.

In an email to a 3M laboratory manager, Professor Giesy described his role as trying to keep “bad papers out of the literature”, because in “litigation situations they can be a large obstacle to refute”.

Professor Giesy was an editor of several academic journals and, in any given year, about half of the papers submitted on PFAS came to him for review.

“Some journals … for conflict-of-interest issues will not allow an industry to review a paper about one of their products. That is where I came in,” he wrote in another email.

“In time sheets, I always listed these reviews as literature searches so that there was no paper trail to 3M.”

Professor Giesy is alleged to have passed confidential manuscripts on to 3M, as well as an email from an EPA scientist detailing its latest PFAS investigations in Athens, Georgia. He allegedly bragged about rejecting the publication of at least one paper containing negative information about PFAS.

In another email chain, a 3M manager was concerned that a study Professor Giesy had drafted was “suggestive” of possible PFAS health hazards and should be cushioned with an accompanying document on the health effects.

“This paper … could set off a chain reaction of speculation that could reopen the issue with the media and move it back to a health story; something up to now we have avoided,” he wrote.

Professor Giesy is based at the University of Saskatchewan in Canada, but he also holds positions with the University of Michigan and several Chinese universities.

An internal 3M document referred to him needing to “buy favours” when developing joint projects with Chinese colleagues “over whom he can exert some influence”.

A spokesperson for the University of Saskatchewan said it had conducted two reviews of Dr Giesy’s conduct.

“We found nothing out of the ordinary or evidence of conflict of interest,” she said.

The university stressed that the “vast majority” of Professor Giesy’s work for 3M was conducted while at Michigan State University, despite evidence of 3M payments to Professor Giesy’s consulting company after he arrived in Canada.

Professor Giesy’s explanations included that these were “possibly” payments for previous work or studies by other employees of his consultancy. “He cannot be absolutely sure of the timing,” the university spokesperson said.

“With respect to the emails … Dr Giesy explained to us that ‘bad papers’ referred to ‘bad science’ or ‘inaccurate’ papers or ‘poorly conducted’ research … and ‘no paper trail to 3M’ was due to the sensitivity of research findings conducted on PFAS produced by companies, primarily in foreign countries, other than 3M.”

But several academics were furious with the university’s position. Professor Arthur Schafer, an expert in applied ethics at the University of Manitoba, slammed the explanation for the “no paper trail” comment as “ludicrously implausible”.

“I don’t think it matters a hoot whether Giesy’s ethically questionable activities all took place prior to his coming on staff at the University of Saskatchewan or whether they continued,” he said.

“The evidence points to deeply troubling conduct which, if confirmed by a proper investigation, should lead to disciplinary action - probably termination, given the seriousness of the behaviour.”

One of the university’s council members, Professor Len Findlay, was unconvinced by the university’s reviews.

“A key question remains: If the University of Saskatchewan had known much sooner about those emails between Giesy and 3M, would they still have recruited him? If so, what does that say about their desperation to buy a more illustrious institutional reputation and ranking through hires?” Professor Findlay said.

“And what about 3M’s agreement to settle out of court, after delaying that action until the very last minute? What does that suggest about the nature of work undertaken on their behalf?”

Court hears how a Fortune 500 company doctored the science:

The actions of Professor Giesy were a jigsaw piece in a much broader puzzle, according to the State of Minnesota. It alleged that 3M:

Formed an internal team to “command the science” on the chemicals, erect “defensive barriers to litigation” and ensure scientific papers did not include information contrary to the company’s “business interests”

Funded friendly research, on the condition the company could edit the draft scientific papers and, on occasion, control whether they were published at all

Referred reporters to “independent third party experts” who were actually carefully vetted, paid for their services and signed confidentiality agreements

Destroyed documents, told staff to stamp all documents relating to PFAS as attorney-client privileged, throw away pencil notes from meetings and not to jot down thoughts because of how they could be viewed during legal discovery. One employee made a note to “clean out computer of all electronic data” on the chemicals.

Decades of inaction

When 3M announced the voluntary phase-out of PFOS in 2000, it was presented as an environmentally responsible decision - costing the company $US480 million in annual revenue - and based on concerns over the discovery of PFOS in the blood of the general population in 1997.

But according to internal documents, the company had actually made that discovery decades earlier, in the 1970s.

Just before the phase-out announcement, the US EPA reviewed a PFOS study in rats, in which all of the offspring of the first generation died and many offspring of the second generation.

“It is very unusual to see such second-generation effects,” the director of its Chemical Control Division wrote.

About that time, scientist Richard Purdy quit 3M and copied the agency in on his resignation letter.

He expressed “outrage” that his colleagues wanted to avoid collecting data on PFOS, which he described as “the most insidious pollutant” since polychlorinated biphenyl (PCB) and “probably worse”.

PCB was an industrial chemical that was banned when it was found to be a human carcinogen.

“I have worked to the best of my ability within the system to see that the right actions are taken on behalf of the environment,” he wrote. “Yet I see slow or no results. I am told the company is concerned, but their actions speak to different concerns than mine.”

The failure of 3M to report information to the EPA on the adverse effects of the chemicals ultimately resulted in a $US1.5 million fine.

In his testimony, Professor Grandjean argued that 3M had documented adverse effects in animals as early as the 1970s, with one researcher warning that PFOS was “certainly more toxic than anticipated”. 3M did not pursue findings of PFAS in the breast milk of animals, and published some of its studies after lags of 25 years, Professor Grandjean found.

Professor Philippe Grandjean of Harvard University. Photo: Supplied

More concerning were several 3M-sponsored studies of its own exposed factory workers that showed elevated rates of prostate cancer, including statistically significant findings.

One paper put the spike in prostate cancer deaths down to chance or because of the higher prevalence of prostate cancer in Minnesota.

“Subsequent analyses provided to 3M … indicate that prostate cancer was actually less prevalent in Minnesota than in the US,” Professor Grandjean wrote.

In 1979, renowned scientist Dr Harold Hodge warned the company that if the chemicals were found to be widespread in the blood of the general population and had long half-lives, “we could have a serious problem”. The phrase was removed in a later document referring to the conversation.

In another internal email, a 3M scientist wrote that one consideration as to whether a study should be done on reproductive effects was “the possibility of finding reproductive effects when conducting such a study”.

Another controversy arose surrounding the work of a University of Minnesota thesis student, Frank Gilliland, who did early studies on 3M’s exposed factory workers. He found signs of hormonal and immune system abnormalities in males. But follow-up studies authored by 3M “undermined” these findings, Professor Grandjean said.

Professor Grandjean has pioneered research into the effects of the chemicals on childhood vaccines, finding that as PFAS exposure doubled, vaccines were about half as effective in children in the Faroe Islands. A “substantial” number of children had such low levels of antibodies that they had virtually no protection against the diseases.

He expressed concern about the scarcity of research into the effect of chemicals on infants and unborn children, who were exposed through cord blood and breast milk and were “likely more vulnerable to toxic effects”.

'A dirty game of survival'

It is no secret that 3M has poured significant funds into sponsoring PFAS research by consultancies and academic institutions. But the court documents indicate the company may have gone further - influencing studies but keeping its fingerprint hidden. According to court documents, the use of a “ghost writer” was floated at a 3M meeting in 2008.

Professor Lisa Bero, of the University of Sydney, is internationally renowned for her investigations into the influence of industry on scientific research, as one of the first authors to scrutinise the tactics used by the tobacco and pharmaceutical companies.

Much of her work has been based on documents that have come to light through litigation.

“It’s directly parallel, I would have to say - the strategies that were used in the PFAS case are really all the same as we’ve seen used across the other industries,” she said.

“Even the wording was identical.”

One of the most interesting elements, she said, was that they all referred to scientific publication strategies.

“That is all about generating evidence to either protect them from litigation or to market their products. It’s not about creating new scientific knowledge.”

The key witness for 3M in the Minnesota case was Ellen Chang, a principal scientist at scientific consultancy Exponent.

In her testimony, she argued that the weight of epidemiological evidence did not prove a causal link between exposure to PFAS and “specific adverse health outcomes in humans”.

Exponent, based in California, has courted controversy on several occasions in the US, with some critics labelling it a “hired gun” producing science to meet the needs of corporations in messy courtroom battles. The firm has come under fire for casting doubt on studies linking second-hand smoke with cancer, as well as rates of lung cancer among mechanics exposed to brakes containing asbestos.

“That criticism is quite simply factually wrong,” an Exponent spokesperson said. “We provide our clients with our engineering and scientific findings, which are frequently not what they would like to hear but rather what they need to know.”

A 2016 study authored by Ms Chang reviewed all available evidence and concluded that PFAS exposure did not increase the risk of cancer in humans.

The study was cited by toxicologists working for Australia’s Department of Defence as part of a human health risk assessment on exposed populations in Australia.

It was also included in a report by the Department of Health’s expert panel on PFAS, which concluded that the current evidence did not support a “large impact” from PFAS exposure on a person’s health.

Professor Nicholas Buckley, of the University of Sydney, who chaired the panel, defended the use of Ms Chang’s studies in its review and argued that the “most importance guidance” came from other independent studies.

“The major potential conflicts of interest for Chang’s 3M-funded reviews were noted in the PFAS report on multiple occasions, and the likely impact of that was considered,” he said.

“Their results get summarised on about half-a-dozen pages in a 400-page report.”

But lawyer Robert Bilott, who led the successful class action against Dupont in West Virginia, criticised the decision.

“Papers prepared years after the fact to serve to manufacture doubt or perpetuate a false perception of uncertainty … with respect to PFOA should not be relied upon or cited as a basis for minimising or ignoring potential health risks,” he wrote.

Dr Fardin Oliaei did not pause when asked whether 3M’s studies on the chemicals could be trusted, responding “of course not”.

As a scientist with the Minnesota Pollution Control Agency, she was one of the first to begin investigating the spread of PFAS chemicals in the state. She alleges she was blocked from conducting her research and eventually forced out of her job, at a time when the agency was headed by Commissioner Sheryl Corrigan, a former high-ranking 3M manager.

“The reality is this is a game, a dirty game of survival, of big industry,” said Dr Oliaei, who settled a whistleblower lawsuit filed in the federal court.

“Seeing other scientists who lose their dignity and sleep in the same bed with this dirty corrupted industry? It’s heartbreaking.

“But when I look at it in a global level ... here’s what it is: You just have to be someone that you can go to bed and put your head in peace on the pillow.”